1. Field
One embodiment of the invention relates to a fuel cell apparatus for use in an electronic apparatus such as a personal computer and to a method of controlling the fuel cell apparatus.
2. Description of the Related Art
Hitherto, in a portable electronic device such as a notebook-sized personal computer, a lithium-ion battery is used as a battery. Recently, also in a portable electronic device, attention is being paid to a fuel cell such as a direct methanol fuel cell (DMFC) as a new power source replacing a lithium-ion battery.
A fuel cell such as a DMFC has a characteristic such that an output voltage decreases as an output current increases. Consequently, the output power of a fuel cell reaches its peak when the output voltage of the fuel cell has a predetermined value. Therefore, many of switching power source circuits each using a fuel cell as a power source operate in a constant voltage control mode for making the output voltage of the fuel cell coincide with a predetermined reference voltage as means for effectively utilizing output power of the fuel cell (refer to Jpn. Pat. Appln. KOKAI Publication No. 2005-56764).
In the device, as the operation time of the fuel cell increases, discharge water increases with a change in output current of a stack. Consequently, a water collecting mechanism is needed.